It is known in the art that 9,9-bis(4-hydroxyphenyl) fluorene (BHPF), one species of dihydroxyaryl fluorene, can be employed in the preparation of thermoplastic condensation polymers including diaryl fluorene carbonate polymers. For example, BHPF is disclosed to prepare random copolymers with bisphenol A and other bisphenols (U.S. Pat. No. 3,546,165) and to prepare block copolymers with bisphenol A (U.S. Pat. No. 3,128,264) and with diorganosiloxanes (U.S. Pat. No. 3,781,378). A process for preparing BHPF homopoly-carbonates is disclosed in JP 63-182,336 (1988) and reported to prepare polymers having high heat resistance, good transparency and a desirable refractive index, which polymers are proposed for use in lenses and automobile body panels.
A range of BHPF-containing carbonate polymers, including BHPF/BA copolymers have been reported and suggested for use in a number of applications. Japanese Patent Publication No. JP 02-304,741 (1990) discloses copolycarbonates of 20 to 90 weight percent BHPF with BA for use in the manufacture of polycarbonates for optical disks. Japanese Patent Publication No. JP 05-155,998 (1993) discloses carbonate polymers containing BHPF and aliphatic units. Japanese Patent Publication No. JP 05-228,350 (1993) discloses gas separation membranes prepared from copolymers of BHPF and BA. Japanese Patent Publication No. JP 06-25,398 (1994) discloses the use of BHPF/BA (41 to 95 mole percent BHPF) copolymers for lenses. Japanese Patent Publication No. JP 06-25,399 (1994) discloses the use of BHPF/BA (1 to 40 mole percent BHPF) copolymers for laser card substrates. Japanese Patent Publication No. JP 06-25,401 (1994) discloses the use of BHPF/BA (70 to 95 mole percent BHPF) copolymers for printed circuit applications.
In U.S. Pat. No. 5,196,479 it is suggested that blends of higher Tg carbonate polymers, such as carbonate polymers based on bisphenol AP, BHPF or tetrabromo bisphenol A, can be prepared with lower Tg carbonate polymers, noting that they may or may not be miscible.
It would be desirable to have an improved carbonate polymer composition possessing a good combination of product properties including processability, impact resistance, solvent resistance, optical clarity, stability and resistance to melting at high temperatures, and physical strength. It would also be desirable to have a relatively uncomplicated production process by which a range such polymers can be prepared to obtain the desired balances of these properties which are typically traded off in obtaining a thermoplastic that is suited for a particular application.